CHOLERA ANTITOXINE. 153 



ditions as favourable as those of the above-described experiment 

 of METSCHNIKOFF and his collaborators. 



A further conclusion to be drawn is that cultivations that 

 have been killed contain only a very small amount of the toxine, 

 and this accounts for the want of success in the attempts to 

 isolate it as a chemical entity, and also the but trifling toxic 

 action of the collodion capsules containing the dead cells. 



As the vitality of the cells grows weaker the proportion of 

 true toxine present also decreases very rapidly, so that in old 

 cultivations or those that have been destroyed there is little 

 poison present except that secondary heat-resisting product that 

 has been described by various observers. This is certainly no 

 longer a true toxine, since it resists boiling and is relatively but 

 slightly poisonous. This poison, too, is only secreted to a small 

 extent, but is, at all events, sufficiently stable to be isolated as 

 a definite substance distinct from the body cells of the vibriones. 

 It has, moreover, a slight power of forming an antitoxine ; it 

 thus shows all the characteristics that belong to Ehrlich's 

 toxoids viz., greatly reduced toxic capacity, greater stability, and 

 the power of forming an antitoxine, as well as of entering into 

 combination. 



Hence, from these considerations, we can conclude with some 

 degree of probability that the cholera vibrio produces a true toxine, 

 an endotoxine, comparable with yeast invertase, which is only 

 separated scantily, if at all, from the living cell, and that this 

 toxine is extremely unstable, and is very readily transformed 

 into a secondary mixture of poisons rich in toxoids. 



At the same time, it is highly probable that, in addition to 

 this poison so scantily secreted, the cholera vibrio, presumably, 

 like all bacteria, also contains in its protoplasm a simple non- 

 specific bacterial protein, which produces symptoms of inflam- 

 mation, as, for example, that of the diphtheria bacillus. Only in 

 this case it is not possible to separate the enzymic poisons so 

 quantitatively as in the case of diphtheria, so that it is difficult 

 here to obtain objective proof whether any such poisonous protein 

 is present, in addition to the specific poisons. 



CHOLERA ANTITOXINE. 



We have shown above that it is probable that there is a cholera 

 toxine which produces antitoxine to a small extent. No decisive 

 unquestionable proof, however, that the serum of the animals in 

 the experiments contains an active antitoxic substance has been 

 given ; and so long as cholera antitoxine has not been actually 



